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Finding the Fourth Proportional to 151.20, 208.64 and 91.40

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Solution

The fourth proportional to 151.20, 208.64 and 91.40 is: 126.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    151.20 : 208.64 = 91.40 : x
  2. Step 2: Convert to fraction form
    151.20/208.64 = 91.40/x
  3. Step 3: Cross multiply
    151.20x = 208.64 × 91.40
  4. Step 4: Simplify right side
    151.20x = 19,068.88
  5. Step 5: Solve for x
    x = 19,068.88/151.20
  6. Step 6: Final answer
    x = 126.12

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.